fix: use basic auth for npm registry access

When username and password are configured in the .npmrc for the
respective scope, use basic auth when getting package metadate from the
npm registry.

packages/@vue/cli/lib/util/ProjectPackageManager.js

@@ -197,7 +197,7 @@ class PackageManager {
     return this._registries[cacheKey]
   }
 
-  async getAuthToken (scope) {
+  async getAuthConfig (scope) {
     // get npmrc (https://docs.npmjs.com/configuring-npm/npmrc.html#files)
     const possibleRcPaths = [
       path.resolve(this.context, '.npmrc'),
@@ -225,8 +225,17 @@ class PackageManager {
       .replace(/https?:/, '') // remove leading protocol
       .replace(/([^/])$/, '$1/') // ensure ending with slash
     const authTokenKey = `${registryWithoutProtocol}:_authToken`
+    const authUsernameKey = `${registryWithoutProtocol}:username`
+    const authPasswordKey = `${registryWithoutProtocol}:_password`
 
-    return npmConfig[authTokenKey]
+    const auth = {}
+    if (authTokenKey in npmConfig) {
+      auth.token = npmConfig[authTokenKey]
+    }
+    if (authPasswordKey in npmConfig) {
+      auth.username = npmConfig[authUsernameKey]
+      auth.password = Buffer.from(npmConfig[authPasswordKey], 'base64').toString()
+    }
   }
 
   async setRegistryEnvs () {
@@ -296,9 +305,13 @@ class PackageManager {
       headers.Accept = 'application/vnd.npm.install-v1+json;q=1.0, application/json;q=0.9, */*;q=0.8'
     }
 
-    const authToken = await this.getAuthToken(scope)
-    if (authToken) {
-      headers.Authorization = `Bearer ${authToken}`
+    const authConfig = await this.getAuthToken(scope)
+    if ('password' in authConfig) {
+      const credentials = Buffer.from(`${authConfig.username}:${authConfig.password}`).toString('base64')
+      headers.Authorization = `Basic ${credentials}`
+    }
+    if ('token' in authConfig) {
+      headers.Authorization = `Bearer ${authConfig.token}`
     }
 
     const url = `${registry.replace(/\/$/g, '')}/${packageName}`